/*  

 * Copyright (c) 2003 The Visigoth Software Society. All rights  

 * reserved.  

 *  

 * Redistribution and use in source and binary forms, with or without  

 * modification, are permitted provided that the following conditions  

 * are met:  

 *  

 * 1. Redistributions of source code must retain the above copyright  

 *    notice, this list of conditions and the following disclaimer.  

 *  

 * 2. Redistributions in binary form must reproduce the above  

 copyright  

 *    notice, this list of conditions and the following disclaimer in  

 *    the documentation and/or other materials provided with the  

 *    distribution.  

 *  

 * 3. The end-user documentation included with the redistribution, if  

 *    any, must include the following acknowledgement:  

 *       "This product includes software developed by the  

 *        Visigoth Software Society (http://www.visigoths.org/)."  

 *    Alternately, this acknowledgement may appear in the software  

 itself,  

 *    if and wherever such third-party acknowledgements normally  

 appear.  

 *  

 * 4. Neither the name "FreeMarker", "Visigoth", nor any of the names  

 of the  

 *    project contributors may be used to endorse or promote products  

 derived  

 *    from this software without prior written permission. For written  

 *    permission, please contact visigo...@visigoths.org.  

 *  

 * 5. Products derived from this software may not be called  

 "FreeMarker" or "Visigoth"  

 *    nor may "FreeMarker" or "Visigoth" appear in their names  

 *    without prior written permission of the Visigoth Software  

 Society.  

 *  

 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED  

 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES  

 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE  

 * DISCLAIMED.  IN NO EVENT SHALL THE VISIGOTH SOFTWARE SOCIETY OR  

 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,  

 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT  

 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF  

 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND  

 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,  

 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT  

 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF  

 * SUCH DAMAGE.  

 *  

 ====================================================================  

 *  

 * This software consists of voluntary contributions made by many  

 * individuals on behalf of the Visigoth Software Society. For more  

 * information on the Visigoth Software Society, please see  

 * http://www.visigoths.org/  

 */

package freemarker.core;

import java.io.IOException;

/**
 * A TemplateElement representing a block of plain text.
 * 
 * @version $Id: TextBlock.java,v 1.17 2004/01/06 17:06:42 szegedia Exp $
 */

public final class TextBlock extends TemplateElement {

    private static final char[] EMPTY_CHAR_ARRAY = new char[0];

    static final TextBlock EMPTY_BLOCK = new TextBlock(EMPTY_CHAR_ARRAY, false);

    // We're using char[] instead of String for storing the text block because

    // Writer.write(String) involves copying the String contents to a char[]

    // using String.getChars(), and then calling Writer.write(char[]).By

    // using Writer.write(char[]) directly, we avoid array copying on each

    // write.

    private char[] text;

    private final boolean unparsed;

    public TextBlock(String text) {

        this(text, false);

    }

    public TextBlock(String text, boolean unparsed) {

        this(text.toCharArray(), unparsed);

    }

    private TextBlock(char[] text, boolean unparsed) {

        this.text = text;

        this.unparsed = unparsed;

    }

    /**
     * Simply outputs the text.
     */

    public void accept(Environment env) throws IOException {

        env.getOut().write(text);

    }

    public String getCanonicalForm() {

        String text = new String(this.text);

        if (unparsed) {

            return "<#noparse>" + text + "</#noparse>";

        }

        return text;

    }

    public String getDescription() {

        String s = new String(text).trim();

        if (s.length() == 0) {

            return "whitespace";

        }

        if (s.length() > 20) {

            s = s.substring(0, 20) + "...";

            s = s.replace('\n', ' ');

            s = s.replace('\r', ' ');

        }

        return "text block (" + s + ")";

    }

    TemplateElement postParseCleanup(boolean stripWhitespace) {

        if (text.length == 0)

            return this;

        int openingCharsToStrip = 0, trailingCharsToStrip = 0;

        boolean deliberateLeftTrim = deliberateLeftTrim();

        boolean deliberateRightTrim = deliberateRightTrim();

        if (!stripWhitespace || text.length == 0) {

            return this;

        }

        if (parent.parent == null && previousSibling() == null)

            return this;

        if (!deliberateLeftTrim) {

            trailingCharsToStrip = trailingCharsToStrip();

        }

        if (!deliberateRightTrim) {

            openingCharsToStrip = openingCharsToStrip();

        }

        if (openingCharsToStrip == 0 && trailingCharsToStrip == 0) {

            return this;

        }

        this.text = substring(text, openingCharsToStrip, text.length

        - trailingCharsToStrip);

        if (openingCharsToStrip > 0) {

            this.beginLine++;

            this.beginColumn = 1;

        }

        if (trailingCharsToStrip > 0) {

            this.endColumn = 0;

        }

        return this;

    }

    /**
     * Scans forward the nodes on the same line to see whether there is a
     * deliberate left trim in effect. Returns true if the left trim was
     * present.
     */

    private boolean deliberateLeftTrim() {

        boolean result = false;

        for (TemplateElement elem = this.nextTerminalNode(); elem != null

        && elem.beginLine == this.endLine; elem = elem

        .nextTerminalNode()) {

            if (elem instanceof TrimInstruction) {

                TrimInstruction ti = (TrimInstruction) elem;

                if (!ti.left && !ti.right) {

                    result = true;

                }

                if (ti.left) {

                    result = true;

                    int lastNewLineIndex = lastNewLineIndex();

                    if (lastNewLineIndex >= 0 || beginColumn == 1) {

                        char[] firstPart = substring(text, 0,

                        lastNewLineIndex + 1);

                        char[] lastLine = substring(text, 1 + lastNewLineIndex);

                        if (trim(lastLine).length == 0) {

                            this.text = firstPart;

                            this.endColumn = 0;

                        } else {

                            int i = 0;

                            while (Character.isWhitespace(lastLine[i])) {

                                i++;

                            }

                            char[] printablePart = substring(lastLine, i);

                            this.text = concat(firstPart, printablePart);

                        }

                    }

                }

            }

        }

        if (result) {

        }

        return result;

    }

    /**
     * Checks for the presence of a t or rt directive on the same line. Returns
     * true if the right trim directive was present.
     */

    private boolean deliberateRightTrim() {

        boolean result = false;

        for (TemplateElement elem = this.prevTerminalNode(); elem != null

        && elem.endLine == this.beginLine; elem = elem

        .prevTerminalNode()) {

            if (elem instanceof TrimInstruction) {

                TrimInstruction ti = (TrimInstruction) elem;

                if (!ti.left && !ti.right) {

                    result = true;

                }

                if (ti.right) {

                    result = true;

                    int firstLineIndex = firstNewLineIndex() + 1;

                    if (firstLineIndex == 0) {

                        return false;

                    }

                    if (text.length > firstLineIndex

                    && text[firstLineIndex - 1] == '\r'

                    && text[firstLineIndex] == '\n') {

                        firstLineIndex++;

                    }

                    char[] trailingPart = substring(text, firstLineIndex);

                    char[] openingPart = substring(text, 0, firstLineIndex);

                    if (trim(openingPart).length == 0) {

                        this.text = trailingPart;

                        this.beginLine++;

                        this.beginColumn = 1;

                    } else {

                        int lastNonWS = openingPart.length - 1;

                        while (Character.isWhitespace(text[lastNonWS])) {

                            lastNonWS--;

                        }

                        char[] printablePart = substring(text, 0, lastNonWS + 1);

                        if (trim(trailingPart).length == 0) {

                            // THIS BLOCK IS HEINOUS! THERE MUST BE A BETTER

                            // WAY! REVISIT (JR)

                            boolean trimTrailingPart = true;

                            for (TemplateElement te = this.nextTerminalNode(); te != null

                                    && te.beginLine == this.endLine; te = te

                            .nextTerminalNode()) {

                                if (te.heedsOpeningWhitespace()) {

                                    trimTrailingPart = false;

                                }

                                if (te instanceof TrimInstruction

                                && ((TrimInstruction) te).left) {

                                    trimTrailingPart = true;

                                    break;

                                }

                            }

                            if (trimTrailingPart)

                                trailingPart = EMPTY_CHAR_ARRAY;

                        }

                        this.text = concat(printablePart, trailingPart);

                    }

                }

            }

        }

        return result;

    }

    /*
     * private String leftTrim(String s) { int i =0; while (i<s.length()) { if
     * (!Character.isWhitespace(s.charAt(i))) break; ++i; } return
     * s.substring(i); }
     */

    private int firstNewLineIndex() {

        String content = new String(text);

        int newlineIndex1 = content.indexOf('\n');

        int newlineIndex2 = content.indexOf('\r');

        int result = newlineIndex1 >= 0 ? newlineIndex1 : newlineIndex2;

        if (newlineIndex1 >= 0 && newlineIndex2 >= 0) {

            result = Math.min(newlineIndex1, newlineIndex2);

        }

        return result;

    }

    private int lastNewLineIndex() {

        String content = new String(text);

        return Math.max(content.lastIndexOf('\r'), content.lastIndexOf('\n'));

    }

    /**
     * figures out how many opening whitespace characters to strip in the
     * post-parse cleanup phase.
     */

    private int openingCharsToStrip() {

        int newlineIndex = firstNewLineIndex();

        if (newlineIndex == -1 && beginColumn != 1) {

            return 0;

        }

        ++newlineIndex;

        if (text.length > newlineIndex) {

            if (newlineIndex > 0 && text[newlineIndex - 1] == '\r'

            && text[newlineIndex] == '\n') {

                ++newlineIndex;

            }

        }

        if (new String(text).substring(0, newlineIndex).trim().length() > 0) {

            return 0;

        }

        // We look at the preceding elements on the line to see if we should

        // strip the opening newline and any whitespace preceding it.

        for (TemplateElement elem = this.prevTerminalNode(); elem != null

        && elem.endLine == this.beginLine; elem = elem

        .prevTerminalNode()) {

            if (elem.heedsOpeningWhitespace()) {

                return 0;

            }

        }

        return newlineIndex;

    }

    /**
     * figures out how many trailing whitespace characters to strip in the
     * post-parse cleanup phase.
     */

    private int trailingCharsToStrip() {

        String content = new String(text);

        int lastNewlineIndex = lastNewLineIndex();

        if (lastNewlineIndex == -1 && beginColumn != 1) {

            return 0;

        }

        String substring = content.substring(lastNewlineIndex + 1);

        if (substring.trim().length() > 0) {

            return 0;

        }

        // We look at the elements afterward on the same line to see if we

        // should strip any whitespace after the last newline

        for (TemplateElement elem = this.nextTerminalNode(); elem != null

        && elem.beginLine == this.endLine; elem = elem

        .nextTerminalNode()) {

            if (elem.heedsTrailingWhitespace()) {

                return 0;

            }

        }

        return substring.length();

    }

    boolean heedsTrailingWhitespace() {

        if (isIgnorable()) {

            return false;

        }

        for (int i = 0; i < text.length; i++) {

            char c = text[i];

            if (c == '\n' || c == '\r') {

                return false;

            }

            if (!Character.isWhitespace(c)) {

                return true;

            }

        }

        return true;

    }

    boolean heedsOpeningWhitespace() {

        if (isIgnorable()) {

            return false;

        }

        for (int i = text.length - 1; i >= 0; i--) {

            char c = text[i];

            if (c == '\n' || c == '\r') {

                return false;

            }

            if (!Character.isWhitespace(c)) {

                return true;

            }

        }

        return true;

    }

    boolean isIgnorable() {

        if (text == null || text.length == 0) {

            return true;

        }

        if (!isWhitespace()) {

            return false;

        }

        // trick here

        boolean atTopLevel = true;

        TemplateElement prevSibling = previousSibling();

        TemplateElement nextSibling = nextSibling();

        return ((prevSibling == null && atTopLevel) || nonOutputtingType(prevSibling))

                && ((nextSibling == null && atTopLevel) || nonOutputtingType(nextSibling));

    }

    private boolean nonOutputtingType(TemplateElement element) {

        return (element instanceof Macro || element instanceof Assignment

        || element instanceof AssignmentInstruction

        || element instanceof PropertySetting

        || element instanceof LibraryLoad || element instanceof Comment);

    }

    private static char[] substring(char[] c, int from, int to) {

        char[] c2 = new char[to - from];

        System.arraycopy(c, from, c2, 0, c2.length);

        return c2;

    }

    private static char[] substring(char[] c, int from) {

        return substring(c, from, c.length);

    }

    private static char[] trim(char[] c) {

        if (c.length == 0) {

            return c;

        }

        return new String(c).trim().toCharArray();

    }

    private static char[] concat(char[] c1, char[] c2) {

        char[] c = new char[c1.length + c2.length];

        System.arraycopy(c1, 0, c, 0, c1.length);

        System.arraycopy(c2, 0, c, c1.length, c2.length);

        return c;

    }

    boolean isWhitespace() {

        return text == null || trim(text).length == 0;

    }
}
